Contactless control system for sanitary equipment - uses variable frequency filter for noise immunity of control switching function

摘要

A contactless control device is esp. for control of sanitized plant. It has an oscillator (3) and a probe (1) detecting the approach of a part of the human body from the resulting earth capacity variation and supplying a switching signal. It is designed to be considerably resistant to noise effects including electromagnetic noise and power supply noise, and to operate reliably using a simple economical construction. - The oscillator is connected to a filter. When the probe is approached the filter resonant frequency is reduced and the filter output voltage varied. When the output voltage varies by a specified amount the switching element is operated.